Cardiovascular System


Major Functions of the Cardiovascular System
Diseases of the circulatory system should never be neglected. Avoid prolonged periods of standing or sitting. The fluid of the coelom containing free mesodermal cells constitutes the blood and lymph. A heartbeat is a two-part pumping action that takes about a second. Each end opens into large vessels that lack true walls and are merely sinus channels.

Also of Interest

Common Diseases of the Circulatory System

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Benefits of black seed oil. Tubes called veins go into your heart. Arteries and veins are also called blood vessels. Blood comes into the atria or top chambers of your heart. Your ventricles, or bottom chambers, pump blood out to every part of your body.

Every part of your body needs food and oxygen for energy. You need energy for your body to work and for you to stay alive. Your heart pumps blood carrying food and oxygen through your arteries. Big arteries carry the blood to your legs and arms. The arteries get smaller and smaller the farther out they go. Little blood vessels called capillaries take blood to your cells.

Everything in your body is made of tiny cells. One of these waste products is a gas called carbon dioxide. The blood in your capillaries picks up the waste products. Capillaries connect to bigger veins. The pumping of your heart pushes the blood through your veins. The chambers on the right side of your heart take care of blood coming back through your veins. First, the blood comes into your right atrium, the top chamber. Your right atrium pumps the blood into your right ventricle, the bottom chamber.

Your right ventricle pumps the blood through an artery into your lungs. It has to get a fresh supply of oxygen. Your lungs take care of both jobs. Carbon dioxide from your blood goes into your lungs. Your lungs get rid of the carbon dioxide when you breathe out. Your lungs get oxygen from breathing in air. The right ventricle pumps blood through the shorter pulmonary circuit while the left ventricle pumps blood through the longer systemic circuit.

Nearly one-forth of the blood that is pump into the Aorta by the Left Ventricle flows to the Kidneys. Excess nutrients are stored in the Live for future needs.

The Liver receives oxygenated blood from a large Artery that branches of the Aorta. The heart also needs a supply of blood for its nourishment. It does not use the blood it pumps for itself. The blood flowing through the heart does not directly serve the heart. Like all other organs the heart muscle has its own blood circuit. The heart gets blood from the coronary arteries that emerge directly from the aorta. Two coronary arteries arise from the aorta just beyond its semilunar valve. The right coronary artery mostly serves the right atrium and right ventricle.

The left coronary artery is much larger and supplies the left atrium and left ventricle. Venules then carry the blood to the coronary veins and back to the right atrium. The pumping action of the heart is controlled by the pacemaker also known as the sino-atrial node SA. It is in the wall of the right atrium. The pacemaker receives messages from the brain.

Two nerves from the medulla oblongata connect to it influencing its rate of contraction. One nerve quickly accelerates the heart rate and the other can quickly reduces it back to resting rate. These messages are transmitted as electrical impulses that cause the atria both left and right to contract. This contraction is called atrial systole.

Contraction of the atria sends blood to the ventricles. The electrical impulse then enters the ventricles at the atrio-ventricular node and travels through the septum to the ventricles at the atrio-ventricular node AV. The ventricles contract and force the blood towards the openings of the arteries, pulmonary artery and aorta. This is called ventricular systole. The rate of heartbeat is very important.

The average healthy person will have a heart rate of about beats per minute. Brain impulses and hormones can change this rate. Also, exercise, temperature, emotions, and shock will increase the heart rate. Relaxation and sleep decrease the rate.

A heartbeat is a two-part pumping action that takes about a second. This contraction pushes blood through the tricuspid and bicuspid valves into the resting lower chambers the right and left ventricles. This part of the two-part pumping phase the longer of the two is called atrial systole. The second part of the pumping phase begins when the ventricles are full of blood. The electrical signals from the SA node travel along a pathway of cells to the ventricles, causing them to contract.

As the tricuspid and bicuspid valves shut tight to prevent a back flow of blood, the semilunar valves are pushed open. While blood is pushed from the right ventricle into the lungs to pick up oxygen, oxygen-rich blood flows from the left ventricle to the heart and other parts of the body.

After blood moves into the pulmonary artery and the aorta, the ventricles relax, and the pulmonary and aortic valves close. The lower pressure in the ventricles causes the tricuspid and bicuspid valves to open, and the cycle begins again. This series of contractions is repeated over and over again, increasing during times of exertion and decreasing while you are at rest.

When the atria are contracting the ventricles are relaxing. This is called ventricular diastole. Likewise, when the ventricles are contracting the atria are relaxing. This is called atrial diastole. The lub sound- quieter, longer, lower pitched- caused by the bicuspid and tricuspid valves closing. A heart murmur is an abnormal sound of the heart.

It is usually an indication of damaged valves. Blood pressure is the blood pressing against the blood vessel walls. It is measured by a sphygmomanometer.

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